To understand this cartoon, you need to recognize that the setting — one or two people on a small, otherwise uninhabited, island with a lone palm tree — is a cartoon meme, and that such a setting is referred to in English by the idiom desert island. (You also, of course, need to recognize the items on the island as desserts; and to know how to spell desert and dessert.)

To understand this strip, you need to know about keyboard shortcuts on a Mac computer, in particular the combination

Command-Z: Undo the previous command. You can then press Command-Shift-Z to Redo, reversing the undo command.

⌘-Z undoes, or reverses, keyboard actions. In the cartoon, the dimwitted Ralph suggests using this computer key combination to reverse events in general — in this case, the falling of the lamp to the floor and the breaking that resulted from the fall. ⌘-Z will fix it!

“Well, there’s your problem right there—you need to sauté the onions in white wine before adding the ginger.”

First, the usual note about what you have to know to understand this cartoon. You have to recognize that the cartoon is set in a baseball stadium during a game (this is fairly easy, though it involves very culture-specific knowledge), and that we’re looking at the catcher and the pitcher conferring on the pitcher’s mound about pitching strategy, a conference in which privacy is often assured by having the two men cover their mouths with their mitts (this is definitely inside-baseball esoterica).